Non-Fermi liquid Behaviors in Quasi-one-dimensional Mn Lattice under Pressure

In situ high pressure powder neutron diffraction of CaMn₂Sb₂ and YbMn₂Sb₂ reveals anisotropic compressibility and an eventual large volume collapse. The trigonal 122 phase with the space group P-3m lattice such as CaMn₂Sb₂ and YbMn₂Sb₂ has been shown to exhibit a plethora of interesting quantum effects ranging from magnetic frustration to “magnetic liquid” states similar to MnSi. The Mn atoms on the honeycomb lattice engender significant influence from nearest neighbor, next nearest neighbor interactions (J₂/J₁). When fit with a classical Heisenberg model on the honeycomb lattice CaMn₂Sb₂ has been shown to be close to a tricritical point. Pressure has been used as a tool to tune the J₂/J₁ ratio by physically pushing atoms together, strengthening interactions and pushing the J₂/J₁ ratio closer to the tricritical point. Powder neutron diffraction experiments reveal a 10% reduction of volume before an eventual volume collapse to a monoclinic P2₁/m phase, analogous to CaMn₂Bi₂, and an incommensurate magnetic structure induced at higher temperatures.